Recently there has been an increase in awareness of work/life fatigue and its debilitating effect on human functionality. It is an accepted fact that increased stress affects mood, performance at work and interpersonal relationships. As more and more people spend a greater amount of their active time (work and leisure) in front of a display, it is becoming increasingly important to enhance the experience.
As an ever increasing number of workers are office based, there is an increasing amount of reported cases of work related stress. Sources of stress often lead to fatigue at the workplace include: environmental conditions, such as poor quality artificial lighting and/or too much or too little ambient lighting; poorly designed displays or (incorrect) and ineffectual visual aids that permit unfettered access to digital data presented on display screens.
In a paper published in “Journal of Behavioural Optometry”; Vol. 7, 1996 Number 5, entitled “Stress and Eye: New Speculations on Refractive Error” by Merrill D. Bowan, there is a discussion and explanation as to a theory of ametropias and that refractive errors are outcomes of resulting physiological strains.
The author proposes a General Adaptation Syndrome (GAS) as a stress adaptive response. It is postulated that visual coping mechanisms are challenged by a variety of conditions so as to produce homeostatic responses that alter scleral and crystalline lens dynamics, leading to posterior chamber distention and hyperopization.
The author measures these as adaptive diseases: myopia, hyperopia and astigmia and attributes their existence as a precursor of adaptation exhaustion exacerbated by stress. It is argued that for the vision specialist, the existence of refractive errors is a cause of physical stress and vice versa.
These are the sorts of stress that are often suffered by employees who spend a large proportion of their working day in front of visual display units (VDUs), screens or other displays. These stresses are often present in the chain of causation leading to posterior chamber distention and hyperopization and which subsequently can give rise to, or exacerbate, fatigue related visual disruption presenting and/or manifesting in coping strategies like monocularity, unstable or unsustainable vergence, double vision and even eye turns. This visual disruption can in turn give rise to fatigue related inability to maintain a good posture, which in turn can increase the risk of repetitive stress injury (RSI), temporary harm or longer lasting injury including muscular skeletal disorders, which can ultimately lead to temporary or permanent disability.
To date there has not been a reliable objective method of assessing risk of over exposure to such displays, regardless of compliance with current health and safety legislation (in many countries including the UK) that recognises that fatigue may also be an overarching potential causation in repetitive strain injury (RSI) type injuries. Such other injuries include a variety of other stress related diseases, such as muscular skeletal disorders (MSDs) as reported by the UK Health and Safety Executive (HSE) in a Report entitled “Better Display Screens” (RR561 in 2007) which referred to aspects of display systems and monitors.
It has been noted, with the proposed introduction, in April 2012 of a revised EU Directive (Directive 90/270/EEC—Display Screen Equipment) on ‘Manual Handling and Display Screen Equipment (DSE), that employers are resisting being placed under increased legislative pressure to ensure that reasonable steps are being taken to prevent and/or mitigate stressors known to be a common risk that debilitates operator performance.
Risk assessments are legally required by various Health and Safety regulators in many jurisdictions. A risk assessment should fully assess all aspects of an employees' workplace, their equipment/tools and normal working conditions. Risk assessments should also be carried out at regular periods, or on demand or when there is a change in equipment, work conditions, environment or equipment operators.
Users or operators who interact with visual display units (VDUs) or Display Screen Equipment (DSE) for even relatively short periods of time, may be susceptible to, and/or at increased risk of, acquiring harmful visual coping strategies characterised by computer vision syndrome (CVS).
CVS is a condition associated with a range or collection of harmful symptoms indicative of the visual systems physiological and/or neurological response to being under strain. Such physiological and/or neurological strain gives rise to what is often referred to as “screen fatigue” associated with a mild form of ‘cyber sickness’ that has been noted to be exacerbated by certain, virtual 3-D technologies being introduced across media, including: micro screen, hand held equipment and mobile devices, as well as static display screen equipment that, following research, now carries a warning that children are particularly susceptible and may suffer long term damage to their visual systems. This is another form of “visual stress” resulting in systemic fatigue.
Visual stress can also trigger the onset of eye ache and tension headaches. If such eye ache and headaches are experienced regularly they can give rise to, or even promote, increased (emotional) psycho-physiological stress, which can manifest itself as performance anxiety. These are often the result of a range of coping strategies, for example when subjected to prolonged use of display screen equipment (DSE) in addition to increased.
The eyes and visual system can therefore be considered to be connected to an organism physically, chemically and emotionally. Therefore, their function or dysfunction is inextricably linked to the well-being of the individual.
This stress related fatigue, if it remains unmitigated, can in turn lead to problems with employee well-being, attendance and/or increased reporting of errors, irascible behaviours, absenteeism and time off as sick. There is also evidence that these effects may be associated with lower employee self esteem, poor morale and an increase in risk of harm through other hazards linked to the workplace resulting in higher staff turnover.
There is therefore an ever-greater need for an apparatus and a related method for determining and measuring fatigue, especially operator fatigue.